The present invention relates to an electric rotating machine including a stator and inner and outer rotors disposed inside and outside the stator, respectively.
Japanese Patent Application First Publication No. 2001-103717 (corresponding to U.S. Pat. No. 6,639,337) discloses an electric rotating machine including a stator having a plurality of circumferentially arranged stator teeth with armature coils, an inner rotor coaxially disposed inside the stator, an outer rotor coaxially disposed outside the stator, and an inverter connected to the stator. The inner and outer rotors are independently driven by supplying a composite current to the armature coils of the stator.